Ok, I can fill this loan without any interest. Just sign a message with the current date and we're good to go.
Will be updated with the TX.
There you go:
-----BEGIN BITCOIN SIGNED MESSAGE-----
This is Nekutasa from bitcointalk.org I am taking a 0.003 btc loan from sulendra12 for 2 days. Date is March 5/2017
-----BEGIN SIGNATURE-----
1KFxi83M67C558ua1qrej4UhsNJXy2kaDP
HxE6TrSg3Zpk/FWj9S4fHIZimibH6gcW0YGNbDsnyS+JIGjifRaS4kYUhopeBNe0wog5NHgCa3s6og05hxrMcT0=
-----END BITCOIN SIGNED MESSAGE-----
Thank you!